Internal combustion engine

Abstract

An internal combustion engine includes: a cylinder in which a piston reciprocates; a cylinder head positioned above the cylinder; a gasket disposed between the cylinder and the cylinder head; a stepped portion formed at an upper end portion of an inner peripheral surface of the cylinder; a ring member having a cylindrical shape provided to the stepped portion; and a seal member that is provided on an upper surface of the ring member and is sandwiched between the ring member and the cylinder head.

What is claimed is: 
     
       1. An internal combustion engine comprising: a cylinder in which a piston reciprocates, the cylinder having an inner peripheral surface partially being directly exposed to an outer peripheral surface of the piston; a cylinder head positioned above the cylinder; a gasket disposed between the cylinder and the cylinder head; a stepped portion formed at an upper end portion of the inner peripheral surface of the cylinder; a ring member having a cylindrical shape provided to the stepped portion; a seal member that is provided on an upper surface of the ring member and is sandwiched between the ring member and the cylinder head, and wherein the seal member is in contact with an upper surface of the ring member and an end portion of a lower surface of the gasket. 
     
     
       2. The internal combustion engine according to  claim 1 , wherein a space is formed between an outer peripheral surface of the ring member and an inner peripheral surface of the stepped portion, and
 the seal member is in contact with both the ring member and the gasket. 
 
     
     
       3. The internal combustion engine according to  claim 1 , wherein
 a space is formed between an outer peripheral surface of the ring member and an inner peripheral surface of the stepped portion, and 
 the seal member is in contact with both the ring member and the cylinder head. 
 
     
     
       4. The internal combustion engine according to  claim 1 , wherein the seal member is formed in an annular shape. 
     
     
       5. The internal combustion engine according to  claim 4 , wherein
 the seal member is hollow along a circumferential direction and is crushed between the ring member and the cylinder head. 
 
     
     
       6. The internal combustion engine according to  claim 5 , wherein a material of the seal member is softer than materials of the ring member and the cylinder head. 
     
     
       7. The internal combustion engine according to  claim 1 , wherein
 an outer peripheral surface of the ring member is a tapered surface such that a diameter of the ring member decreases downwards, and 
 an inner peripheral surface of the stepped portion is an inclined surface parallel to the tapered surface of the ring member. 
 
     
     
       8. The internal combustion engine according to  claim 1 , wherein, below the stepped portion, the inner peripheral surface of the cylinder is directly exposed to the outer peripheral surface of the piston. 
     
     
       9. The internal combustion engine according to  claim 8 , wherein, above the stepped portion, the ring member is disposed between the inner peripheral surface of the cylinder and the outer peripheral surface of the piston. 
     
     
       10. The internal combustion engine according to  claim 1 , wherein, only below the stepped portion, the inner peripheral surface of the cylinder is directly exposed to the outer peripheral surface of the piston. 
     
     
       11. The internal combustion engine according to  claim 9 , wherein, only above the stepped portion, the ring member is disposed between the inner peripheral surface of the cylinder and the outer peripheral surface of the piston. 
     
     
       12. The internal combustion engine according to  claim 1 , wherein the ring member includes a first portion facing the stepped portion and a second portion facing a side surface of the gasket, and
 wherein the seal member is in contact with the second portion and the cylinder head. 
 
     
     
       13. The internal combustion engine according to  claim 1 , wherein the seal member abuts the ring member and the cylinder head. 
     
     
       14. The internal combustion engine according to  claim 1 , wherein the seal member further abuts the gasket.